How to Wire EFI with a Custom Harness - Completing the Circuit

Completing a late-model EFI engine swap is challenging enough without taking wiring into consideration, and while the wiring aspect of the swap is usually one of the last things people think of, it is one of the first things that should be figured out before you grab the first wrench. A bargain of an engine find might turn out to be not so much of a bargain if you can't source the proper wiring for the engine to make it run. While the go-to engine right now might be the 4.6L Four-Valve "Coyote" engine found in the '11-'14 Mustang GT (and available through Ford Racing's crate engine program), there are plenty of Ford engine offerings sitting in salvage yards (and possibly in your own backyard) that would make for a great engine swap into a classic Mustang or Ford.

Just such an example can be found between the front fenders of the '68 Mustang coupe seen here at Gillis Performance Restorations (GPR). Rusty Gillis is the man behind this project, and while the aforementioned Coyote would certainly be a welcome addition to this tidy little coupe, it is a budget shop project mainly being built from cast off items to offer a rolling business card of GPR's paint and body abilities. Since the body and paint are the main focus, the drivetrain consideration for the project basically fell into the realm of cheap and reliable, with EFI, and an overdrive trans to make it a nice cruiser. Rusty didn't need 500 horsepower to show off his shop's paint and metal working skills. To that end, he just happened to have a '96 Thunderbird sitting behind the shop that used to be his father's daily driver. The 4.6L Two-Valve engine under the hood would be the perfect swap candidate—low mileage, reliable, fuel injected, and best of all, free!

Tackling the 4.6L Two-Valve's physical installation would be a breeze for the likes of Rusty and his shop, however, the wiring was a different story altogether.

"I'm an old school carburetor guy; EFI wiring scares me," Rusty explained to us. It's good news for Rusty then that we know EFI wiring and live and breathe these swaps here at Modified Mustangs & Fords. While the Three-Valve modular in our Generation Gap project and Four-Valve Coyote modular in our Colt of Personality project both are/will be wired via Ford Racing Control Pack wiring kits, older Four-Valve and Two-Valve modulars, and more obscure swap candidates like the 3.8L supercharged V-6 from the Thunderbird Super Coupe, the 2.3L turbocharged I-4 from the Thunderbird Turbo Coupe and Mustang SVO, and other Ford engine packages can be a little more challenging to wire. However, if you're smart, you'll pick up the phone and order a Telorvek wiring panel system from The Detail Zone, a division of Ron Francis Wiring.

The panel-based wiring concept preached by the Ron Francis folks means anyone, even Rusty, can wire his/her EFI engine project quickly and easily. The fuse panel and ECM mount wherever you find convenient—even all the way back in the trunk. Ron Francis makes this easy with a neat, compact panel. Then you simply follow the well written directions to connect your EFI engine's components (inputs and outputs) and route their un-terminated wire ends to the panel's location. Ron Francis gives each circuit 20 feet of high-quality automotive grade wiring that is labeled every 10 inches. Simply cut the wire to length, terminate the ends, and secure the wire ends to the panel. What could be easier? Follow along as we look over the installation as Rusty and his son, Brian, wire their very first EFI wiring system in the following photos.